Variable pitch propeller



Nov. 8, 1932. s. B. SMITH 1,886,602

VARIABLE PITCH PROPELLER I Filed Jan. 16 1931 4 Sheets-Sheet 1 INVENTOR ATTORNEYS Novl 8, 1932; s. B, SMITH VARIABLE PITCH PROP-ELLER Filed Jan. 16. 1931' 4 Sheets-Sheet 2 A'rrbausys Nov. 8, 1932. s. B. SMITH 1,836,602

VARIABLE PITCH PROPELLER Filed Jan. 16 1931 4 Sheets-Sheet 3 INVENTOR 5/7/ 0 3. Spy/I'll ATTORNEYS Patented Nov. 8 1932 UNITED STA ES PATENT OFFICE SAMUEL B. SMITH, F ROCKY RIVER, OHIO VARIABLE PITCH PROPELLER Application filed January 16, 1931'. Serial No. 509,148.,

enced in designing and building variable pitch,

propellers which are practical and stand up when in service. Moreover, heretofore attempted types of variable pitch propellers were adapted with difiiculty to standard makes of motors and to standard airplanes and airships, chiefly because the variable pitch propellers and the operating means, therefor, require considerable room and necessitate either a special-propeller shaft or crankshaft which is somewhat longer than the one usually employed. Again no means have been provided for positively and adjustably limiting the pitch of the propeller. w The general object of the invention is to overcome the foregoing difliculties and disadvantages of theprior art by providing a variable pitch propeller which is adaptable to standard propeller shafts, and which has improved means controlling the pitch of the blades. v a

It is also an object of the invention to provide adjustable means for. positively limiting the pitch of the propeller blades.

The above and other objects of the invention are achieved by the apparatus illustrated in the accompanying drawings and described below, it being understood that the invention is not limited to the specific details shown and described. V In the drawings: I V

Figure 1 is a longitudinal sectional view through the hub embodying the invention;

Figure 2 is a sectional view'taken on line 2-2 of Figure 1;

Figure 3 is a sectional view taken on line 33 of Figure 1;.v 1 Figure 4 is a sectional view taken on line 4-4 of Figure 1;

F igure 5 is an enlarged sectional view taken on line 5-5 of Figure 1;

Figure 6 is a fragmentary view taken on line i-6 of Figure 10;

Figure 7 is a sectional view taken on line 7-7 of Figure 6;

Figure 8 is a sectional view taken on line 8-8 of Figure 6;

Figure 9 is an elevation of the gear carrying member and worm incorporated in the 5 invention; and

Figure 10 is an enlarged sectional view taken on line 10-10 of Figure 5.

The present invention relates to and presents certain improvements over the copendw ing application ofvGlenn R. Brooks, Serial Number 449,802, filed May 5, 1930.

Referring to the drawings, the numeral 11 indicates a propeller shaft or crankshaft of a motor (not shown) which shaft 11 is journaled in suitable bearings 12 in a motor frame 13,

Keyed to the shaft 11 by a key 16 is hub l lformed with blade carrying sleeves 15, which may be formed with the hub or which may be secured thereto by welding or brazing. The hub 14 is fixed to the shaft 11 so that it cannot work loose by threading the end of the shaft 11 and providing a cap 17 which is locked in place by a sleeve 18, threaded in opposite hand to the cap 17 n The cap 17 and sleeve 18 are locked togetherby a removable spring 19 fitting in aligned holes therein.

' A propeller blade 21 having a cylindrical end 22, threaded atits end with abuttress so thread 23 is received in each sleeve 15. A

' combined nut and worm gear 24 is threaded on the thread 23 and locked in place by screws 25. In order to allow the blades to turn freely in the sleeves even when under great operating stress, a plurality of ball bearings 26 are provided between the ends 22 of the blades and the sleeves 15. In addition the ends 22 of the blades are preferably formed with cylindrical bosses 27, which are jour- Q.

naled by suitable bearings, 28 in sockets formed in the hub 14.

Each blade assembly is held in place by I means of a ring 31 whlch is buttress threada 36 and are provided with worm gears 39 ed with the sleeve 15. Each assembly is preferably packed with grease which is retained by a asket 32. 1

Re erring particularly to Figure 5, it will be seen that the hub 14 is formed with four housings 33, 34, 35 and 36, of which 33' and 34,-and 35 and 36 respectively are opposite and parallel. J ournaled inithe housings 33 and 34 are worms 37 and 38 which engage with the worm gears 24 on the inner end of the propeller blades 21. The shafts of the worms 37 and 38 are extended adjacent the housing and 40. 7 y In the housing 36 is (see Figure 10) journaled the means through which the worm gears 39 and 40 are driven, which means also serves to adjustably limit the extent of pitch clutches 55 .and 56 of the claw type.

movement of the blades. These means include a. pair of leftand right-threaded worms 42 and 43, which are secured on opposite ends of a tube 44. The worms are threaded unto the tube 44 and the worm 42 is turned on very tightly whilethe worm 43 is not run down so tight, but is locked by means of a pin 49, which engages in slot 57 of tube 44.

' The worms 42 and 43 are j ournaled on arod '45, which is threaded along itsmiddle and which is supported and positioned by plugs 46 and 47 screwing into the end of the housing 36. The plug 46 and shaft make a sliding but non-rotative fit as at 48, so thatthe rod cannot turn after the parts are assembled. J ournaled on the tube 44 is a gear 50 hav-, ing a hub 51 which .is positioned midway between the worms 42 and 43 b means of sleeves 52. Slidably mounted on' t e tube 44 at the ends of the hub 51 of the gear 50 are collars 53 which are urged towards the hub 51 through the agency of curved spring washers 54. The contacting ends of the collars 53 and hub 51 are formed with opposite direc(ton ee Figures 6 and 8.) Thetube 44 is formed-with a slot 57 and the collars 53 are splined to the tube b pins 58 which engage in the slot. A pair 0 round nuts 61 are threaded on the rod I 45 and are provided with lugs 62 which slide housing 35,

means are provided to rotate the gear 50,

in the slot 57. The lugs 62 engage with the pins 58 at the end of the travel of the nuts 61 to disengage the'clutches as hereafter more ful Il y1 explained. e housing 35 is in. reality solid a'nd serves merely as a counterbalance for the housin 36 and the means therein. Any amount 0 metal necessary to correctly counterbalance the unit can be removed from both ends of the after which they are closed by suitable caps. y f

Referring particularly to Figures 1 and 2,

which means include a gear carrying member 64 splined to sleeve 65, fixed to a heargear 50 upon movement of the member 64.

In order to control the position of the member'64 the bearing 66is formed with a peripheral groove, in which is, received a ring7l which can be moved in the groove by a handle 72 through any suitable operating means 73. The ring 71 is provided with a plurality of inwardly extending pins 74 which move in circumferential slots 75 in the bearing 66 and sleeve 65 and slots 76 at an angle to the circumferential in the gear carrying member 64. In this manner when the ring'71 is rotated through an arc the gear carrying member is moved longitudinally or axially.

The shaft 11 is preferably threaded and rovided with a nut 77 which secures the caring 12 in place. Any suitable gasket means may be provided as at 78 and 79 between the stationary and oving portions of from the housing 36.1 The pin 49 is removed and the worm 43 is screwed, off the tube 44, allowing the collar 53 and spring washer 54 to be pulled oif the tube, which allows the rod 45 with the nuts 61 thereon to be removed.

The nuts 61 are now adjusted to any determined position apart and' from the ends of the rod. The above operations are reversed and the-unit is replaced in the housing 36.

With the motor running, the pitch of the propeller blades can be changed by moving the ring 71 through the agency of the operating means 73. The circumferential movement of the pins 74 secured to the ring 71 is transmitted into axial movement of the member 64 by way of the slots'75and 76, so

that either worm 67 or 68 can be brought into engagement with the gear 50. The

worms 67 and 68 do not rotate but the rotation of the 50 to trave relative movement between the gear and worm is the same as if the worm were turning.

propeller hub 14 causes the gear around the wormfso that the 'As the nuts 61 are somewhere intermediate of the pins 58 the turning gear 50 will transmit motion through one or the other of the clutches 55 or 56, dependant on which.

way the ar is turning, to one of the collars 53, whic in turn will rotate tube 44 and the worms 42 and 43 fixed thereto;

The worms 42 and 43 co-operate with the worm,gears 39 and 40 to turn the worms 37 and 38 which engage with the gears 24 secured to the inner ends of the propeller blades 21. The gear reduction is very large, so that a large number of revolutions of the propeller hub causes a very small movement of the blades about their longitudinal axes. The blades can be stopped at any pitch desired by merely returning the worm carrying member 64 to itsneutral position. By moving the member 64 in the other direction the pitch is changed in a reverse direction.

In this manner the pitch of the propeller blades can be changed and adjusted at will while the ropeller is in operation. The plurality oi frictionless bearings 26 which journal the blades in the sleeves 15 allow the pitch to be varied even when the blades are under the most severe operating stress.

The mechanism encased in the housing 36 limits the extent to which the pitch of the blades can be changed. For example: With the nuts 61 substantially as shown in the drawings, assume that the member 64 has been moved axially to throw one of the worms 67 or 68 into engagement with the gear 50. The rotating gear 50 will drive either the one or the other of the collars 53 through either clutch 55 or 56, depending on its direction of rotation. The collar 53will turn-tube 44 due to the pin 58 engaging in the slot 57, which tube will. in turn rotate the worms 42 and 43, and through the other gearing change the blade pitch. Now the tube 44 when it turns will also turn the nuts 61 as the lugs 62 thereof engage in the slot 57 which causes the nuts to travel along the threaded rod 45 which is held from turning by the square end 48.

The continued rotation of the gear will thus cause the nuts 61 to engage with the one or the other of the pins 58 held by a collar 53 which will cause the-collar to be moved outwardly on the tube 44 against the action of the spring 54, which movement will disengage the clutch 55 or 56, so that further rotation of the gear 50 will not transmit any motion to the tube 44 or worms 42 and 43.

Rotation of the gear 50 in the opposite direction will cause the nuts 61 to travel in the other direction to disengage the clutch adjacent that end of travel in a like manner. It will be understood that the clutches 55 and 56 are of opposite direction so that when one is disengaged by the nuts 61, the other will slip so that no drive is given the tube 44. By' initially adjusting the positions of the I nuts 61 on the threaded rod 45, as above described, it is possible to provide any desired limits beyond which the blade pitch cannot be changed. .In this manner the blades can sired pitch. This construction also eliminates the necessity of pitch angle recording means.

In accordance with the patent statutes only one specific embodiment of the invention has been described and illustrated. However, it will be understood that the scope of the invention is not limitedthereto,

vmounted adjacent said hub, means for moving said gear means relative to each other to cause them to engage whereby the pitch of the propeller blade can be varied and ads justable -means in said first named gear means for positively controlling the limits of the pitch variation.

, 2. In a variable pitch'propeller, a hub, a propeller blade mounted in said hub, gear means carried on said'hub and connected with said blade, gear means mounted adjacent said hub, means to engage said last named gear means with said'first named gear means, wherebythe pitch of the propeller blade can be varied and adjustable means in said first named gear, means for positively controlling the limits of the pitch variation.

3. In a variable pitch propeller, a hub, a propeller blade mounted in said hub, gear means carried on said'huband connected 'with said blade, gear means mounted adjacent said hub, means to engage said last named gear means with said first named gear means, whereby the pitch of the propeller blade can be varied and adjustable means for positively controlling the limits of the pitch variation.

4. In a variable pitch propeller, a hub, a propeller blade mounted in said hub, gear means carried on said hub and connected with said blade, non-rotative gear means mounted adjacent said hub, means for moving said gear means relativeto each other to cause them to engage whereby the pitch of the propeller blade can bevaried and means;

for positively controlling the limits of the pitch variation.

5. In a variable pitch propeller, a hub, a propeller blade mounted in said hub, gear means carried ,on'said hub and connected with said blade, gear means mounted adjacent said'hub, means to engage said last named gear means with said first named gear means, whereby the pitch of the propeller blade can be varied and adjustable means in said first named gear, said adjustable means including a clutch connection in said "first named gear means and means for disengaging said clutch connection at the desired limit of the pitch variation. be adjusted exactly and positively to any de- 6. In a variable pitchpropeller, a hub, a

propeller blade mounted in said hub, gear means carried on said hub and connected with said blade, gear meansmounted adjacent said hub, means to'engage said last cent said hub, means to engage said last named gear means with said first named gear means, whereby the pitch of the propeller blade can be varied and adjustable means in said first named gear, said adjustable means including a clutch connection in said first named-gear means.

8. In a variable pitch ropeller, a hub, a propeller blade mounted in said hub, means for changing the pitch of the propeller while in operation and adjustable means for positively controlling the limits of pitch variation.

9. In a variable pitch propeller, a hub, a propeller blade mounted in said hub, means for changing the pitch of the propeller while in o ration and adjustable means for positive y controlling the limits of pitch varia tion, said adjustable means including a clutch connection. in the first named means and means for disengagin said clutch connection at the desired limit 0 the pitch variation.

10. In a variable pitch propeller, a hub, a

propeller blade mounted in said hub, means for changing the pitch of the'propellerwhile in operation and adjustable means for positively controlling the limits of pitch variation, said adjustable means including a clutch connection in the first named means.

11. In a variable pitch propeller, a hub, a propeller blade mounted, in said hub, gear a means carried with said hub, and connected with said blade, non-rotative gear means mounted adjacent said hub, means rotatable about the hub axis for moving said last named gear means axially of said hub to cause the engagement of the ar means whereby the pitch of the prope er blade can be varied and means for positively controlling the lim-' its of itch. variation.

12. n a variable pitch propeller, ahub, a

' propeller blade mounted in said hub, gear 1n said hub and adapte for movement about' means carried with said hub and connected with said blade, a sleeve, spaced spiral gears on said sleeve, and a shifting means having a pin and slot connection with the sleeve for shifting said sleeve on the hub to cause the spiral gears to selectively engage with said first named gear means. i

13. Ina combination in a variable pitch propeller, a hub, a. pro ller blade mounted a longitudinal blade axis, gear means carried with said hub and connected to said blade,

.a gear carryin .member mounted adjacent said hub for sli ing movement, gears mounted in spaced relation on said gear carrying member, means rotatable about the hub axis for moving said gear carrying member along the hub to engage the one or the otherof the gears with said gear means on the hub whereby the blade pitch can be changed, and

means for positively controlling the hmits of pitch variation.

14. In combination in a Variable pitch propeller, a hub,- a propeller blade mounted in said hub and adapted for movement about alongitudinal blade axis, gear means carried with said hub and connected to said blade, a

gear carrying member mounted adj acent said hub for sliding movement, gears mounted in spaced relation on said gear carrying member and means makinga slot and pin connection with saidgear carrying member and rotatable about the hub axis for moving said gear carrying member along the hub to engage the one or the other of the gears with said gear means on the hub whereby the blade pitch can be changed.

15'. In a variable pitch propeller, a hub, a propeller blade mounted in said hub, gear means carried with said hub and connected with said blade, non-rotative gear means mounted adjacent said-hub and means rotatable about the hub axis for shifting said last named gear means along said hub to cause the engagement of the gear means whereby the pitch of the propeller blade can be varied and adjustable means in said first named gear means for positively controlling the limits of the pitch variation. I I

16. In a variable pitch propeller, a hub, a propeller blade mounted in said hub, gear means carried with said hub and connected with said blade, non-rotative gear means mounted adjacent said hub and means rotat-' able about the hub axis for moving said last named gear means axially of said hub to cause the engagement of the gear means whereby the pitch of the propeller blade can be varied and adjustable'means in said first named gear means for positively controlling the limits 0f the pitch variation, said adjustable means including-a clutch connection insaid first named gear means and means for disengaging said clutch connection at the desired limit of the pitch variatlon.

17. In a variable pitch propeller, a hub, "a,

propeller blade mounted in said hub, gear means carried with said hub and connected with said blade, non-rotative gear-- means the engagement of the gear means whereby v the pitch of the propeller blade can be varied and adjustable means in said first named gear the pitch variation said adjustable means inmeans for positively controlling the limits of l pitchvariation.

SAMUEL B. SMITH.

eluding a clutch connection in said first 

